Lubricating device for sewing machine loop-takers



Jan. 9, 1945. F. PARRY 2,367,046

LUBRICATING DEVICE FOR SEWING MACHINE LOOP-TAKERS Filed Sept. 5, 1942 VV I 221.

[Fan/i Parry Patented Jan. 9, 1945 UNITED STATES LUBRICATING DEVICE FORSEG MACHINE LOOP-TAKERS Application September 3, 1942, Serial No.457,148

16 Claims.

This invention relates to loop-taker mechanisms for sewing machines and,more particularly, to loop-takers of the vertical-axis rotary hook type.

The invention has for its primary object to provide means insuringautomatic delivery of lubricant in controlled quantity, during theoperation of the sewing machine, to the thread-carrier raceway of avertical-axis rotary loop-taker from a substantial supply of lubricant.

It is a further aim of the invention to effect the delivery of lubricantto the loop-taker raceway solely while the machine is in operation andfrom a supply of lubricant disposed above the level of the loop-taker.

With these and other objects in view, as will hereinafter appear, theinvention comprises the devices, combinations and arrangements of partsdescribed in connection with the accompanying drawing, which illustratesa preferred embodiment of the invention and in which:

Fig. l is a front side elevation, partly in vertical section, of atwo-needle sewing machine containing the improved lubricating device.Fig. 2 represents an enlarged vertical section of one of the rotaryloop-takers of the machine. Fig. 3 represents an enlarged verticalsection of the externally threaded stem employed in conjunction with theloop-taker shaft for insuring the delivery of lubricant to theloop-taker raceway during the operation of the machine.

The sewing machine shown in the accompanying drawing has a frameincluding a horizontally disposed work-supporting bed-plate I, from oneend of which rises the standard 2 of a bracketarm terminating at itsfree end in a head 3 overhanging the work-support. Journaled forvertical reciprocation in the bracket-arm head 3 is a needle-bar 4carrying at its lower end atransverse holder 5 for a pair of verticallydisposed needles 6 which are laterally aced from each other lengthwiseof the bed-plate I.

The work is advanced crosswise of the bedplate by a feed-dog I whichoperates through the work-support and which may be actuated in any usualor suitable manner. Yieldingly opposed to the work-engaging movements ofthe feed-dog I is a conventional presser-foot 8.

Complemental to the respective needles 8 in the formation oflock-stitches are two loop-takers in the form of rotary hooks 9 disposedbelow the work-support I. As the rotary hooks 9 are of substantially thesame construction, the right hand hook illustrated in Fig. 2 will bereferred to in the description.

The rotary hook 9 has an upwardly open cupshaped body including ahorizontally disposed bottom wall It! and a cylindrical side wall It.The side wall H of the rotary hook is cut away to provide aneedle-thread loop seizing and spreading beak 12; said side wall I l ofthe rotary hook being internally provided with a raceway i3. Journaledin the raceway I3 of the rotary hook is a thread-carrier it which isrestrained in a conventional manner against rotation with the rotaryhook.

The rotary hook 9 is carried by the upper end of a vertically disposedrotary shaft i5 which, in the present case, is integral with the bottomwall 10 of the hook. While it is preferred to have the rotary hook 9integral with its shaft [5, it will be apparent that the rotary hook maybe detachably or otherwise secured to the hook-shaft in any usual orpreferred manner. The axis of rotation of the rotary hook shaft I5 issubstantially parallel to the needle 8 and is therefore substantiallynormal to the horizontal plane of the work-support I.

The hook-shaft I5 is rotatably journaled in vertically spaced lugs l6and ll of a hook-saddle or bracket 18 disposed below the work-support iand'supported by conventional means. The upper bracket-lug It has avertical opening 19 to receive a ball-bearing 20 in which is Journaledthe upper portion of the hook-shaft [5. The lower lug I! of the bracketl8 also has a vertical opening 2| to receive a bearing-bushing 22 inwhich the lower portion of the hook-shaft I5 is journaled; saidbearing-bushing 22 being suitably secured in the bracket-lug [1.

Between the bracket-lugs l9, H, the hookshaft I5 carries a spiral pinion23 having its hub 23' secured upon said shaft by a set-screw 24. Theupper end of the pinion-hub 23' engages a ball thrust-bearing'25 setinto the opening l9 of the bracket-lug l6 below the ball-bearing 20;said thrust-bearing 25 being preferably spaced from the shaft l5 andbeing adapted to absorb upward thrusts imposed upon said shaft by thedriving connections therewith. The pinion 23 is engaged by the usualspiral driving gear (not shown) carried by the bed-shaft 28; the drivingconnections for the hook-shaft It! being such that the hook 9 rotatestwice for each complete reciprocation of the needle.

The lower end of the hook-shaft l5 terminates within the bushing 22 andis provided with an axial cylindrical opening 21 having a conicallydownwardly flaring lower end 28. with the upper end of the hook-shaftopenin Connected 21 and preferably axially of said opening is the lowerend of a substantially straight duct 29 extending upwardly through thehook-shaft l at an inclination to the axis of rotation of said shaft;whereby the upper end ofthe duct 29 is eccentric to said axis. The upperend of the duct 29 is connected by a radial duct 30 in the bottom wallll) of the hook with a duct 3| provided in the hook side wall H andterminating in the hook raceway l3. The connected ducts 29 and 30together constitute a centrifugal pump for delivering lubricant to theraceway l3 of the loop-taker.

Set into the shaft-bearing aperture of the bushing 22, below the shaftI5, is the cylindrical base 32 of a tubular reduced stem 33. Thestationary stem 33 extends vertically upwardly into the hook-shaftopening 21 to terminate short of the upper end of said opening; saidstem 33 being externally provided with a spiral thread 34 suitablyrelated and complemental to the cylindrical inner wall of theshaft-opening 2'! to insure delivery of lubricant upwardly into thecentrifugal pump duct 29 upon rotation of the shaft l5.

The stem 33 has a reduced neck 33' between the the raceway l3 and isdischarged through the recess 35 and the connected ducts 36 and 37.

When the machine is brought into operation, the rotating cylindricalwall of the shaft-opening 21 cooperates with the stem-thread i l toprevent the lubricant, which is supplied through the bore of the stem33, from being by-passed and discharged through the ducts 3B and 37!.The shaft-opening 21 and the stem-thread 33 therefore function, in theoperation of the machine, as a pump-seal for the by-pass provided in thelubricant-conducting connections between the reservoir and the rotaryhook raceway i3. Being thus prevented from being lay-passed, thelubricant is caused to enter the shaft-duct 29. The vertically inclinedshaft-duct 29 pumps the lubricant by centrifugal force to the upper endstem-base 32 and the lower end of the stema discharge-aperture 31provided in the bracket- 1' lug IT. A wick 38 is preferably disposed inthe longitudinal bore of the stem 33 to retard the flow of lubricantthrough said bore and also to prevent the formation of air-bubbles inthe stembore.

Connected to the stem-base 32 to deliver lubricant to the longitudinalbore of the tubular stem 33 is one end of a lubricant conduit 39extending lengthwise of the bed-plate I. At its opposite end, theconduit 39 is suitabl connected to receive lubricant from a drip-feedreservoir 40 of substantial size; said reservoir being disposed abovethe bed-plate l and being, in the present case, built into thebracket-arm standard 2. Another conduit 4| is similarly connected to thereservoir. 40 to deliver lubricant to the left hand rotary hook. Thereservoir 40 is provided with means for manually controlling thequantity of lubricant supplied to conduits 39 and 4|, and for manuallyshutting off the supply of lubricant; the present reservoir constitutinga duplex arrangement of the built-in reservoir illustrated and describedin my prior patent application Serial No. 423,429, filed December 18,1941, to which reference may be had for a more complete understanding ofthe details of construction of the reservoir. However, it is to beunderstood that the present invention is not limited to any specificreservoir construction, as conventional sight-feed oil-cup devices maybe employed for supplying lubricant to the improved lubricantfeedingdevice.

The lubricant gravitationally supplied to the bore of the stem'33 incontrolled quantity spills from the upper end of said stem and, when themachine is out of operation, dribbles downwardly externally of the stemwithin the hook-shaft opening 21. Consequently, when the machine isidle, the lubricant is by-passed from delivery to of said duct, fromwhich it is delivered in the usual manner to the thread-carrier racewayiii of the rotary hook. This arrangement has the advantage of insuringan early supply of lubricant to the raceway l3 after the machine isbrought into operation, while at the same time controlling the quantityof lubricant delivered.

Having thus set forth the nature of the invention, what I claim hereinis:

In a sewing machine, a vertically disposed rotary loop-taker shaftprovided at the lower end thereof with an axial opening, a loop-takercarried by the upper end of said shaft for rotation therewith and havinga thread-carrier raceway, a thread-carrier journaled in said raceway andrestrained against rotation with said loop-taker, lubricant-conduitconnections between said axial opening of the loop-taker shaft and saidraceway, a stationary tubular stem extending upwardly into andcomplemental to the inner wall of said axial opening of the loop-takershaft in providing a pump-seal for the lower end of said opening duringthe operation of the machine, said stem and the wall of said openingproviding therebetween a lubricant by-pass permitting drainage oflubricant from the lower end of said shaft when the machine is out ofoperation, a

. lubricant-supply reservoir, and lubricant-conducting connections withsaid reservoir for supplying lubricant through the bore of said tubularstem.

2. In a sewing machine, a vertically disposed rotary loop-taker shaftprovided at the lower end thereof with an axial cylindrical opening, alooptaker carried by the upper end of said shaft for rotation therewithand having a thread-carrier raceway, a thread-carrier journaled in saidraceway and restrained against rotation with said loop-taker, astationary tubular stem extending upwardly into and complemental to theinner wall of said axial opening of the loop-taker shaft in providing apump-seal for the lower end of said opening during the operation of themachine, one of the complemental pump-seal members being provided with aspiral thread disposed in close proximity to the other pump-seal member,a lubricant-supply reservoir, lubricant-conducting connections betweensaid reservoir and said tubular-stem for supplying lubricant through thebore of said stem, and lubricant-conducting connections between saidopening of the loop-taker shaft and said raceway of the looptaker.

3. In a sewing machine, a vertically disposed rotary loop-taker shaftprovided at the lower end thereof with an axial cylindrical opening, aloop-taker carried by the upper end of said shaft for rotation therewithand having a threadasoaccs end thereof with an axial opening, aloop-takercarried by the upper end of said shaft for rotation therewithand having a thread-carrier raceway, a thread-carrier journaled in saidraceway and restrained against rotation with said looptaker, astationary and externally spirally threaded tubular stem extendingupwardly into and complemental to the inner wall of said opening of theloop-taker shaft in providing a pumpseal for the lower end of saidopening duringthe operation of the machine, means for supplyinglubricant through the bore of said stem, a lubricant duct in said shaftextending upwardly from said opening and inclined to the rotationaxis ofsaid shaft, and lubricant-conducting connections between the upper endof said duct and said raceway.

5. In a sewing machine, a vertical-axis rotary loop-taker shaft providedat its lower end with an axial opening and having a longitudinal boreextending upwardly from said opening at an inclination away from therotation-axis of the shaft, a rotary loop-taker carried by the upper endof said shaft and having a thread-carrier raceway, lubricant-conductingconnections between said bore of the loop-taker shaft and said racewayof the loop-taker, a stationary tubular stem extending upwardly into andcomplemental to the inner wall of said opening of the looptaker shaft inproviding a pump-seal for the lower end of said opening during theoperation of the machine, said stem and the wall of said openingproviding therebetween a lubricant bypass permitting drainage oflubricant from the lower end of said shaft when the machine is out ofoperation, means for supplying lubricant through the bore of said stem,and a member provided with a lubricant-discharge port, said port beingdisposed below and connected with said axial opening of the loop-takershaft.

6. In a sewing machine, a vertically disposed rotary loop-taker shaftprovided at the lower end thereof with an axial opening, a loop-takercarried by the upper end of said shaft for rotation therewith and havinga thread-carrier raceway, a thread-carrier journaled in said raceway andrestrained against rotation with said loop-taker, a stationary tubularstem extending upwardly into and complemental to the inner wall of saidopening of the loop-taker shaft in providing a pump-seal for the lowerend of said opening during the operation of the machine, means forsupplying lubricant longitudinally through the bore of said stem, andcentrifugal-pump means connected with said opening and havinglubricantconducting connections with said raceway.

7. In a sewing machine; a vertically disposed rotary loop-taker shaftprovided at the lower end thereof with an axial opening, a loop-takercarried by the upper end of said shaft for rotation therewith and havinga thread-carrier raceway, a stationary tubular stem extending upwardlyinto and complemental to the inner wall of said opening of theloop-taker shaft in providing a pump-seal for the lower end of saidopening during the operation of the machine, said opening havinglubricant-conducting connections with said raceway, and said stem andthe wall of said opening providing therebetween a lubricant bypasspermitting drainage of lubricant from the lower end of said shaft whenthe machine is out of operation, and means for gravitationally supplyinglubricant through the bore of said stem.

8. In a sewing machine, a vertically disposed rotary loop-taker shaftprovided at the lower end thereof with an axial opening, a loop-takercarried by the upper end of said shaft for rotation therewith and havinga thread-carrier raceway, a stationary tubular stem extending upwardlyinto and complemental to the inner wall of said opening of theloop-taker shaft in providing a pump-seal for the lower end of saidopening during the operation of the machine, said opening havinglubricant-conducting connections with said raceway, and said stem andthe wall of said opening providing therebetween a lubricant bypasspermitting drainage of lubricant from the lower end of 'said shaft whenthe machine is out of operation, a wick filling the bore of said tubularstem, and means for gravitationally supplying lubricant through thewick-filled bore of said stem.

9. In a sewing machine, a loop-taker supporting. bracket, abearing-bushing carried by said bracket, a loop-taker shaft journaled insaid bearing-bushing for rotation about a vertical axis, said shafthaving the lower end thereof terminating within said bushing andprovided with an axial opening, an externally spirally threaded tubularstem extending upwardly into said axial opening of the loop-taker shaftand complemental to the inner wall of said opening in providing apump-seal for the lower end .of said opening during the operation of themachine, said stem having the base thereof secured in said bushing belowsaid shaft, a loop-taker carried by the upper end of said shaft andprovided with a thread-carrier raceway having lubricant-conductingconnections with said opening, and means for supplying lubricant throughthe bore of said tubular stem.

10. In a sewing-machine, a loop-taker supporting bracket, abearing-bushing carried by said bracket and provided with alubricant-discharge port, a loop-taker shaft journaled insaidbearing-bushing for rotation about a vertical axis, said shaft havingthe lower end thereof terminating within said bushing and provided withan axial opening, a loop-taker carried by the upper end of said shaftand provided with a threadcarrier raceway, a tubular stem extendingupwardly into said axial opening of the loop-taker shaft andcomplemental to the inner wall of said opening in providing a pump-sealfor the lower end of said opening during the operation of the machine,said stem having a base fitted in said bushing in spaced relation to thelower end of said shaft and below the level of said discharge port ofthe bushing, means for supplying lubricant through the bore of saidtubular stem, and means for conducting lubricant from said opening tosaid raceway of the loop-taker.

11. In a sewing machine having a frame including a. horizontallydisposed work-support, in combinatfon, a vertically reciprocatoryneedle, a looptaker supporting bracket disposed below said work-support,a bearing-bushing carried by said bracket and provided with alubricant-discharge port, a loop-taker shaft i urnaled in saidbearingbushing for rotation about an axis substantially parallel to thepath of needle-reciprocation, said shaft having the lower end thereofterminating within said bushing and provided with an axial opening, aloop-taker carried by the upper end of said shaft and having athread-carrier raceway, a wick-filled tubular stem extending upwardlyinto said axial opening of the loop-taker shaft and complemental to theinner wall of said opening in providing a pump-seal for the lower end ofsaid opening during the operation of the machine, said stem having thebase thereof secured in said bushing, and said stem being formed toprovide in the bushing a lubricant-collection recess disposed below saidpump-seal and open to said discharge port, a lubricant-reservoirdisposed above said work-support, a conduit connected to said reservoirfor gravitationally supplying lubricant through the bore of said tubularstem, and means including a centrifugal pump for conducting lubricantsupplied through said stem to said raceway of the loop-taker.

12. In a sewing machine, a vertical-axis rotary loop-taker having athread-carrier raceway, said loop-taker having a lubricant-duct leadingto said raceway, a lubricant-supply reservoir disposed above the levelof said loop-taker and having lubricant-conducting connections with saidlubricant-duct of the loop-taker, said lubricant-conducting connectionsincluding a lubricant by-pass effective when the machine is out ofoperation for diverting lubricant from delivery from said reservoir tosaid lubricant-duct of the loop-taker, and means for rendering saidby-pass functionally ineffective when the machine is brought intooperation.

13. In a sewing machine, a vertically disposed rotary shaft having alongitudinal bore, a looptaker carried by the upper end of said shaftfor rotation therewith and having a thread-carrier raceway, athread-carrier journaled in said raceway and restrained against rotationwith said loop-taker, a lubricant-supply reservoir disposed above thelevel of the loop-taker, lubricant-conducting connections between saidreservoir and said shaft bore, said connections including a lubricantby-pass effective when the machine is out of operation to divert thelubricant from passing through said bore, means brought into action uponoperation of the machine for rendering said by-pass functionallyineffective, and lubricantthereof with an axial opening, a loop-takercarried by the upper end of said shaft and having a thread-carrierraceway, lubricant-conduit connections between said axial opening of thelooptaker shaft and said raceway, a lubricant-supply reservoir disposedabove the level of said loop taker, lubricant-conducting connectionswith said reservoir for delivering lubricant into said axial opening ofthe loop-taker shaft, said axial opening comprising a lubricant by-passeffective when the machine is out of operation for divcrting lubricantfrom delivery from said reservoir to said raceway, and means renderedeffective upon operation of the machine for functionally closing saidby-pass.

15. In a sewing machine, a vertically disposed rotary loop-taker shaftprovided at the lower end thereof with an axial opening, a loop-takercarried by the upper end of said shaft and having a thread-carrierraceway, lubricant-conduit connections between said axial opening of thelooptaker shaft and said raceway, a lubricant-supply reservoir disposedabovethe level of said looptaker, lubricant conducting connections withsaid reservoir for delivering lubricant into said axial opening of theloop-taker shaft, said axial opening comprising a lubricant by-passeffective when the machine is out of operation for diverting lubricantfrom delivery from said reservoir to said raceway, and a pump-sealrendered effective for functionally closing said by-pass when themachine is brought into operation.

16. In a sewing machine, a vertical-axis rotary shaft having at itslower end an axial opening and having a longitudinal bore extendingupwardly from said opening at an inclination to the axis of rotation ofsaid shaft, a loop-taker carried by the upper end of said shaft forrotation therewith, said loop-taker having a thread-carrier raceway, astationary tubular stem extending upwardly into said axial opening ofthe rotary shaft, means for supplying lubricant through said stem, meanseffective during rotation of said shaft for feeding lubricant, suppliedthrough said stem, upwardly into the inclined bore of the shaft, andlubricant-conducting connections between the upper end of said bore andsaid raceway.

FRANK PARRY.

